Controllable stitch fingers for sewing



April 23, 1963 F. D. MOCANN CONTROLLABLE STITCH FINGERS FOR SEWING Filed March 3, 1961 use 9 7 W 0 D w C F H .m C!

Z i ATTORNEY United States Patent. Ofice 3,086,485 Patented Apr. 23-, 1963.

3,086,485 CONTROLLABLE STITCH FINGERS FOR SEWING Francis D. McCann, Kenilworth, N.J., assignor to The Singer Manufacturing Company, Elizabeth, N.J., a corporation of New Jersey Filed Mar. 3, 1961, Ser. No. 93,098 4 Claims. (Cl. 11216) This invention relates to sewing and more particularly to improved means for sewing with controlled quantities of thread contained in the stitches and also relates to improved means for producing invisible seams on full fashioned hosiery.

' My prior copending patent application Serial No. 835,- 875 filed August 25, 1959, now United States Patent No. 3,046,920, issued July 31, 1962, discloses and claims a wheel or cup-feed sewing machine equipped with a pair of stitch fingers mounted so that the fingers can be moved relatively to each other in such a manner as to permit the production of tight or loose stitches. It tight stitches were desired, the two fingers were moved close together. If loose stitches were desired, the two fingers were moved farther apart. In my previous application Serial No. 835,875 supra, the pair of stitch fingers could be moved toward or away from one another while the sewing operation was being performed, but no provision was made for withdrawing or inserting one stitch finger during the sewing operation. Therefore, one of the principal objects of the present invention is to provide an improved means for controlling one or more of the stitch fingers of a sewing machine.

Another object of the present invention is to provide a sewing mechanism having improved means for inserting and/or Withdrawing a stitch finger without stopping the sewing machine.

A further object of the present invention is to provide an improved means for sewing a tight seam on the foot of a stocking and for sewing a loose seam on the leg portion of the same stocking.

A still further object of the present invention is to provide an improved arrangement for mounting a pair of stitch fingers.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby, will be readily understood by those skilled in the art.

In the drawings:

FIG. 1 is a fragmentary horizontal sectional View of a cup-feed sewing machine, similar to the sewing machine shown in United States Patent No. 2,334,672, and embodying the present invention,

FIG. 2 is an enlarged view showing a portion of the mechanism of FIG. 1 and illustrating stitches being formed around one stitch finger while the other stitch finger is withdrawn from engagement with the stitches being formed,

FIG. 3 is a view similar to FIG. 2 but showing stitches being formed about both stitch fingers taken as a pair, and

FIG. 4 is an exploded perspective view showing parts of the mechanism illustrated in FIGS. 1 to 3 inclusive.

Referring in detail to the drawings, there is shown a sewing machine embodying one form of the invention and comprising a machine frame having a standard 21 which rotatably supports, on a fixed axis, an inner feed-cup 22. The standard 21, in a conventional manner (not shown), also supports a movable vertical cylindrical sleeve which in turn rotatably supports an outer feed-cup 23. The outer feed-cup 23 cooperates with the inner feed-cup 22 and the two feed-cups 22 and 23 are positively driven in synchronism in such a manner as to support and feed material past stitch forming devices.

In the sewing machine shown, the stitch forming devices comprise a thread carrying needle 24 carried by an endwise reciprocatory needle bar 25, an oscillatory thread looper 26 and an oscillatory spreader 27. The needle bar 25, the looper 26, and the spreader 27 are, in a well-known manner, operated by mechanisms carried by the standard 21, these parts being properly timed and actuated to form a two-thread over seam.

The cup-feed sewing machine disclosed in my copending application Serial No. 835,875, now United States Patent No. 3,046,920, supra, is provided with a stitch finger, equivalent to stitch finger 28, overlying the feed-cups 22 and 23 at the stitching point. The stitch finger 28 comprises a substantially conical blade 29 formed integral with a shank 31 having a pair of elon-. gate holes 32-32. The shank 31 and thus the blade 29 are adjustably held to a support 33 disposed within an upturned peripheral flange 34 of the inner feed-cup 22 by a pair of screws 36-36. The support 33, in turn, is secured to the standard 21 by means of an angle bracket 37. As is conventional in cup-feed machines of the class herein being considered, the stitch finger overlies the feed-cups 22 and 23 at the stitching point and the stitches produced by the cooperation of the needle 24, looper 26 and spreader 27 are formed and set about the stitch finger to minimize distortion of the marginal edges of the material. My previous copending application also provides a front or outer stitch finger. However, the mechanism of the present disclosure is an advance in the art in that, as shown in the drawing forming part of the present specification, the outer stitch finger 58, which has a slightly curved blade 59 and shank 61, has capacity for bodily movement longitudinally of itself in a curvilinear path.

The outer stitch finger 5-8 is supported in the following manner. A bracket having two substantially semicylindrical parts 66 and 67 is clamped to the vertical cylindrical sleeve 20 by means of a pair of screws 68. The part 66 at a location midway between its ends is provided with a countersunk hole 69 adapted to receive a screw 71. The lower end of the screw 71 is threaded into a hole 72 formed between the two ends of a lever 73, the screw 71 acting as the pivot for swingably mounting the lever 73. One arm 74 of the lever 73 carries an upstanding handle 76 and the other arm 77 of the lever 73 has a threaded hole 78 which accommodates a screw 79. The screw 79 passes through an unthreaded hole 81 in the shank 61 of the outer stitch finger 58 and thus pivotally supports the finger '58 from the free end of the arm 77.

In operation, the present device functions in the following manner. If the operator desires to produce an open seam, she grasps the handle 76 and turns the lever 73 in a counterclockwise direction about the screw 71 until the outer stitch finger 58 assumes the position (FIG. 3) in which the blade 59 is positioned adjacent to and substantially parallel with the blade 29 of the stitch finger 28. When the finger 58 is in the position shown in FIG. 3, the stitch forming instrumentalities 24, 26, and 27 set stitches about both fingers 28 and 58 as a pair, thereby producing an open seam. If the operator wishes to produce a tight seam, she grasps the handle 76 and turns the lever 73 in a clockwise direction about the screw 71 until the outer stitch finger 58 assumes the withdrawn position shown in FIG. 2. When the finger 58 is withdrawn, the stitch forming instrumentalities 24, 26 and 27 set stitches about the single finger 28 and thereby produce a tight seam. Because the outer stitch finger 58 moves longitudinally in a curvilinear path which is substantially parallel to the blade 29 of the stitch finger 28, the blade 59 can be withdrawn or inserted while the sewing machine is producing stitches. Because of this it is possible to sew a tight seam on the foot of a stocking and without stopping the sewing machine to sew a loose seam on the leg portion of the same stocking.

While the foregoing description has been limited to the application of the improved pair of stitch fingers to a sewing machine having feed wheels or cups, it will be understood that the improved stitch fingers of the present invention may be used with other types of sewing mechanisms, as for example, as part of overedge sewing machines, as part of sewing attachments, or as part of straight stitch sewing machines.

Having thus described the nature of the invention, what I claim herein is:

1. A sewing machine having stitch forming instrumentalities including a thread carrying needle; work feeding mechanism for advancing work past said stitch forming instrumentalities; a first stitch finger having a blade so positioned and arranged that said stitch forming instrumentalities when operating will form and set stitches about the blade of said first stitch finger; a second stitch finger having a blade which in its active position is located adjacent to and parallel with the blade of said first stitch finger, said second stitch finger when in its active position being so positioned and arranged that said stitch forming instrumentalities when operating will form and set stitches about the first and second stitch fingers taken as a pair; and means for moving said second stitch finger from said active position to an inactive position in which the blade of said second stitch finger is longitudinally moved away from the blade of said first stitch finger, said means for moving said second stitch finger being such that the blade of the second stitch finger always moves in a path that is substantially an extension of a line parallel to the blade of the said first stitchfinger.

2. A sewing machine having stitch forming instrumentalities including a thread carrying needle; work feeding mechanism for advancing work past said stitch forming instrumentalities; a first stitch finger having a blade so positioned and arranged that said stitch forming instrumentalities when operating will form and set stitches about the blade of said first stitch finger; a movable stitch finger having a blade which may assume both an active and inactive position and its blade when in its active position being located adjacent to and parallel with the blade of said first stitch finger, said blade of said movable stitch finger when in its active position being so positioned and arranged that said stitch forming instrumentalities when operating will form and set stitches about the blade of the first and movable stitch fingers taken as a pair; and means for moving said movable stitch finger from said active position to an inactive position in which the blade of said movable stitch finger is longitudinally moved away from the blade of said first stitch finger, said means for moving said movable stitch finger being such that the blade of the movable stitch finger always moves in a path that is substantially an extension of a line parallel to the blade of said first stitch finger.

3. A sewing machine as set forth in claim 1 in which the means for moving the second stitch finger comprises a lever, means for swinging said lever, and means carried by said lever for moving said second stitch finger.

4. A sewing machine as set 'forth in claim 2 in which the means for moving the movable stitch finger comprises -a lever, means for pivotally mounting said lever, a handle carried by said lever, and means carried by said lever for moving said movable stitch finger longitudinally when said handle is used to swing said lever on its pivot.

References Cited in the file of this patent UNITED STATES PATENTS 721,315 Malsch Feb. 24, 1903 2,012,560 Goodman Aug. 27, 1935 2,031,831 Hausbeck Feb. 25, 1936 FOREIGN PATENTS 39,401 Germany June 3, 1887 

1. A SEWING MACHING HAVING STITCH FORMING INSTRUMENTALITIES INCLUDING A THREAD CARRYING NEEDLE; WORK FEEDING MECHANISM FOR ADVANCING WORK PAST SAID STITCH FORMING INSTRUMENTALITIES; A FIRST STITCH FINGER HAVING A BLADE SO POSITIONED AND ARRANGED THAT SAID STITCH FORMING INSTRUMENTALITIES WHEN OPERATING WILL FORM AND SET STITCHES ABOUT THE BLADE OF SAID FIRST STITCH FINGER; A SECOND STITCH FINGER HAVING A BLADE WHICH IN ITS ACTIVE POSITION IS LOCATED ADJACENT TO AND PARALLEL WITH THE BLADE OF SAID FIRST STITCH FINGER, SAID SECOND STITCH FINGER WHEN IN ITS ACTIVE POSITION BEING SO POSITIONED AND ARRANGED THAT SAID STITCH FORMING INSTRUMENTALITIES WHEN OPERATING WILL FORM AND SET STITCHES ABOUT THE FIRST AND SECOND STITCH FINGERS TAKEN AS A PAIR; AND MEANS FOR MOVING SAID SECOND STITCH FINGER FROM SAID ACTIVE POSITION TO AN INACTIVE POSITION IN WHICH THE BLADE OF SAID SECOND STITCH FINGER IS LONGITUDINALLY MOVED AWAY FROM THE BLADE OF SAID FIRST STITCH FINGER, SAID MEANS FOR MOVING SAID SECOND STITCH FINGER BEING SUCH THAT THE BLADE OF THE SECOND STITCH FINGER ALWAYS MOVES IN A PATH THAT IS SUBSTANTIALLY AN EXTENSION OF A LINE PARALLEL TO THE BLADE OF THE SAID FIRST STITCH FINGER. 